Rainfall and Net Infiltration Probabilities for Future Climate Conditions at Yucca Mountain

Long, Austin; Childs, Stuart W.; ,

Rainfall and Net Infiltration Probabilities for Future Climate Conditions at Yucca Mountain

by Austin Long, Univ of Arizona, Tucson, United States,
Stuart W. Childs, Univ of Arizona, Tucson, United States,

Document Type: Proceeding Paper

Part of: High Level Radioactive Waste Management 1993

Abstract:

Performance assessment of repository integrity is a task rendered difficult because it requires predicting the future. This challenge has occupied many scientists who realize that the best assessments are required to maximize the probability of successful repository siting and design. As part of a performance assessment effort directed by the Electric Power Research Institute, the authors have used probabilistic methods to assess the magnitude and timing of net infiltration at Yucca Mountain. A mathematical model for net infiltration previously published incorporated a probabilistic treatment of climate, surface hydrologic processes and a mathematical model of the infiltration process. In this paper, we present the details of the climatological analysis. The precipitation model is event-based, simulating characteristics of modern rainfall near Yucca Mountain, then extending the model to most likely values for different degrees of pluvial climates. Next the precipitation event model is fed into a process-based infiltration model that considers spatial variability in parameters relevant to net infiltration of Yucca Mountain. The model predicts that average annual net infiltration at Yucca Mountain will range from a mean of about 1 mm under present climatic conditions to a mean of at least 2.4 mm under full glacial (pluvial) conditions. Considerable variations about these means are expected to occur from year-to-year.

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